Editor's note: This is the seventh in a series of stories dealing with emergency preparedness in the 10-mile evacuation zone around Vermont Yankee nuclear power plant in Vernon.
BRATTLEBORO -- Even if an emergency situation was to develop at Vermont Yankee nuclear power plant in Vernon, a release of deadly radiation wouldn't occur immediately, said Neil Sheehan, spokesman for the Nuclear Regulatory Commission.
"In the event of even a severe accident, it will unfold over a matter of days," said Sheehan.
A reactor can't explode like a bomb, he said, because the fuel used is enriched to about 6 percent, as opposed to the 90-percent enrichment needed for a nuclear weapon.
And, he said, there are barriers between the fuel and the environment, including the cladding around the fuel pellets, the reactor cooling system and the containment building.
In 2007, the NRC conducted the State-of-the-Art Reactor Consequence Analyses (SOARCA) to develop what it considered a more realistic study of the potential consequences of a severe nuclear power plant accident.
"Existing resources and procedures can stop an accident, slow it down or reduce its impact before it can affect public health," concluded the study.
"Even if accidents proceed uncontrolled, they take much longer to happen and release much less radioactive material than earlier analyses suggested," continues the study.
In addition, the study
In the case of an evacuation, emergency responders would take a "keyhole approach," he said.
"People think a release of radiation can travel in a 360-degree radius," said Sheehan. "It's not possible based on the law of physics. The plume of radioactive materials will follow prevailing winds."
The area affected by that plume is called the keyhole, he said.
"That's where emergency responders would focus their protective actions, whether that's an evacuation, a shelter in place or the use of potassium iodide."
Though he did not minimize the impact of the Fukushima disaster, Sheehan said even that didn't happen overnight and there was time to evacuate the population.
In the United States following Sept. 11, 2001, all nuclear power plants were required to install back-up generators and pumps.
"Even if they lose all other lines of defense there are ways to get water into the reactor and into the spent fuel pool," said Sheehan.
At the plant level there are regulations in place that require operators to have certain processes and procedures in place to respond to an event, said Mike McKenney, Yankee's Emergency Preparedness Manager.
"If control room operators recognize a condition that warrants entry into the emergency plan, they enter that process," he said.
Entergy, which owns and operates Yankee, maintains a simulator at its headquarters on Old Ferry Road in Brattleboro.
"It allows them to train and practice many different things," said McKenney. "One of them is entry into the emergency plan."
"The more they do it, the better they get," said Rob Williams, spokesman for Vermont Yankee. "These activities are driven by procedure and it's not a matter of memorization by the operators. Every step is directed by procedure."
Howard Shaffer, a start-up engineer at Yankee in 1972 and a member of emergency planning for four different nuclear power plants, said in case of an accident, the first step is declaring a general emergency and activation of the emergency plan.
Personnel then assemble and staff emergency operations centers at the plant, local, state and federal levels, he said.
A system developed after the Three Mile Island accident is put into play to all the NRC to monitor plant instruments.
If it appears that the plant is not able to provide core cooling, and the situation could eventually lead to core damage and release, a precautionary evacuation would be recommended to the governor by the Vermont Department of Health.
On Wednesday, the Reformer will look at the difficulties that will need to be overcome if the Bellows Falls Union High School is needed as a reception center to process evacuees.
Bob Audette can be reached at firstname.lastname@example.org, or at 802-254-2311, ext. 160. Follow Bob on Twitter @audette.reformer.